The Wolves aren't trading Williams. They have been evaluating talent and spreading the minutes around so far this season, but last night Adelman must have wanted to win against his old team because, for the first time this year, he went with an 8-man rotation, and Williams is in it.
Johnson is by far the weak link in the Wolves' starting line-up: that's who they'll try to upgrade. Pierce would not be a bad fit for them--the Wolves need a "closer" as well as a floor-spacer--but the available desirable players from the Wolves are the following: Johnson, Barea (that experiment failed fast), Darko, and Ellington. Randolph is trash but he's surely available too. They're the players a team with an available "upgrade" SF would have to accept from the Wolves in a trade.